Vibratory latching device



ug. 27,- 1946. R, B. IMMEL VIBRATORY LATGHING DEVICE Filed Mroh 25, 19442 sheets-sheet l lNvNToR j /QcMOhB/mme ATTORNEY Patented Aug. 27, 1946VIBRATORY LATCHING DEVICE` 1'italph B. Immel, Wilkinsburg, Pa., assignorto' VJesting-house Electric Corporation, East Pittsburgh, Pa., acorporation of `Pennsylvania Application March 25, 1944, serial No.52,8;060'

My invention relates to shock-responsive latching devices for preventingfailure or faulty operation of apparatus, especially electriccontac/tors, under impact or shock conditions.

It has been proposed and undertaken to prevent electric relays andswitches from uncontrolled operations when exposed to shock orvibrations by providing them with a latching device which, usuallyinoperative, is placed into latching condition by means of a mechanicalvibratory system that responds more readily to shock than the apparatusto be protected and locks the apparatus in position as long as the shockof its vibratory effect persists.

A general object oi' my invention is to improve latching devices andshockproof apparatus of the type just mentioned so as to increasetheirrange of response and render their adjustment less exacting than inthe known devices.

The vibratory system in thel known shock-responsive latching devices,usually composed of a movable Weight and a spring, is ratherrcritical asto the adjustment necessary for covering a satisfactory range of low andhigh impact forces. It may occur that a device which workssatisfactorily on low impact forces responds toa lesser degree on nighimpact blows and vice versa, such a device may also be exposed toimpacts of a frequency too different from the natural frequency of theweight and spring combination to be'sufciently within the rangecovered'by the damped resonance characteristic of the latching device.Hence, it is a more speciiic object of the invention to provide alatcning device that responds more safely to shock frequencies of widelydifferent magnitudes.

Another object of my invention is to provide a shock responsive lockingor latching device, in accordance with the foregoing object, that lendsitselic readily for application with different types of electricalapparatus and can be manufactured or tested as a separate latching unit.

In order to achieve these objects, a shock-responsive latching deviceaccording to the invention has a support or frame structure separablyattached to the apparatus to be latched and serving as a holder for anormally inoperative latch as well as for a plurality of mechanicaloscillatory systems of difierent oscillation characteristics which arearranged to operate and control the latch independently of one anotherso that any of the systems is capable of moving the latch into latchingor locking position when responding to shock. In order to obtain thedesired difference in oscillation characteristics, the mechan- 5 cmims.(ci. 74--527l 2 ical oscillators may'v have different naturalfrequencies and/ or different damping.

According to a preferred embodiment-of my invention, I provide a deviceof tlie type just men;- tioned with a number of independently movableweights of substantially equal mass and dimensions and attach theretoacorresponding number of springs of' different elastici-tyV or stiffnessso that the oscillators have different natural frequencies because ofthe 'different springs',

According to still another feature of the invention, the plurality ofweightsare'all movably mounted for reducing motion about a common pivotaxis so that their planesof motion are in parallel to one another,l andeachappertaining spring is a substantially straight rod or strand shapedbody located substantially in parallel to the other springs and ofsimilar over-all length so that the fasteningpointsof the'y springs lieon a line in parallel to the justmentioned pivot' axis more speciiicallythese springs are fastened to a portion of the latching lever locatednear the fulcrum of the lever.

These objects and featuresA will be fully understood from the followingdescription of the embodiments illustrated in thel drawings. n

Figure 1 is a top view of a contactor provided with a shock responsivelatching` device according to myfinvention; y

Fig. 2 is a part-sectional side'el'evation of the same contacter;

Fig. 3 is another part-sectional side elevation seen from the sameviewpoint as jFig'.` 2, the sectional parts of Fig. 3 beingin thevplanedenoted by the dot-and-dash line III-III in Fig. 1.

Fig. 4 shows a sectional` view of the latching device separate' fromthe, contactor` with the latching lever ininoperative'position. y y

Fig. 5 is an illustration similar to that of Fig. 4 but' showing thelatching device in operativecondition;

Fig. 6 is abottom Viewy ofthe'latching, device according to Figs. 4 and5; y

Fig. 7 is a part-sectional and perspective View of the same device;` v'y v y Fig. 8 representszafront View of a different embodiment of thelatching device; and

Fig. 9 is a perspective 'View'l of, one of the 'mechanical oscillatingsystems of the deviceaccording to Fig. 8.

Referring to Figs. l, 2, and3,l the illustrated contactor has a magneticframe structure l which carries a magnet core 2 and a coil 3' placedaround the core. An abutmentK4 member 4 is mounted on the magneticstructurel and hasrabracket'por# tion which extends towards the area infront of thefmagnet core. The abutment member 4 3 and the adjacent endof the structure I form a corner at 6 which serves as a dihedral pivotbearing for the armature 1. i beveled so as to form a knife-type edgewhich engages thepivot bearing. A weight 8 is'rmly i secured tothearmature 1, and so is a bracket 9 which forms an abutment'for acoiled compres- The armature is sion spring whose'other end is bracedagainst an abutment formed by the portion 5 of the member 4. A latchmember is also rigidly secured to I the armature for a purpose to bedescribed hereinafter.

. Two contact members I I are mounted on an in- I sulating carrier I I'secured to the armature 1 and.y Y

are each connected by a flexible cable I2 with two terminals I3respectively. Each contact II l cooperates` with one oftwo stationarycontacts 1 VIllwhich are provided with respective terminals I5. Blowoutcoils I6 serve to quench the interrupting arcs occurring betweeneachpair of contacts II and I4 during the interrupting operai tion.v Thestationary contacts I4, their terminals I5, the blowout coils I6, andthe terminals I3 of the movable contact II are mounted on a'comi monbase I1 molded of insulating material which is rmly secured to themagnetic structure I. The base I1 has a recess or groove I8 in itscenter 1 portion and a ridge I9 which traverses the recess in order toincrease the mechanical strength of i the molded body I1.

The armature assembly, including the armature proper and the elements 9,28, Il and II 1 attached thereto,'is so biased by the spring I0 that thepivot edge of the armature 1 is held against the dihedral pivot bearingat 6 (Fig. 3). 1In this manner, the armature assembly is constrained toperform angular movements about the axis of the pivot bearing towardsand away from the magnet'core. The force of spring I5 has also acomponent which biases the armature assembly away from thel magnet coreand towards a stationary stop formed at 5 (Fig. 3) by the portion l 5 ofthe abutment member 4. When the armature rests against the stop, themovable contacts II are separated from the stationary contacts I4 (Fig.2) so thatr the circuit between each pair of `terminals `I3 and I5 isopened. When the relay lcoil 3V is energized, the armature 1 isattracted by the magnet core. 2 and moves its contacts II into circuitclosing position.

In order to prevent the above described contactor from performingundesired operations `when subjected to shock and vibration, especially`as occurring on naval vessels due to the loperation of their internalequipment or by contact `with external objects, a latching device isprolvided. This latching device includes a substantially U-shapedsupport or frame structure 2 I con- Referring to Figs. 4, 5, and 6, achannel-shaped presses against the latching lever 23 so as to hold it inits inoperative position illustrated in F1gs. l, 3, and 4. The lever 23has an opening at 25 for engagement with the latch 20 ofthe armature 1(Fig. '3) when the armature is in contact closing position. A third pin3i) also secured between the two legs of the U-shaped structure 2lserves as a pivot for four weights denoted by 3l, 32, 33' and 34. TheVpins 23, 21 and 35 are preferably riveted to the support 2I at one orboth of their ends.

`Each of the weights 3|, 32, 33 and 34 is capable of oscillationindependent of the other weights and has two projections such as thosedenoted by 5I, 52 which face the lever 23 and serve to move the leverinto latching position against the force of spring 28. Four wire springs4I, 42, 43 and'44 are at one end rmly secured to the weights 3l, 32, 33,andV 34, respectively. The other ends of the springs pass through' anopening in an extension 36 of the latching lever 23.

VThe springs have the tendency to hold each' Y ing device and theapparatus on which it is latching lever 23 has its flange portions 24fulv Qcrumed about a pin 2B which is mounted between the two parallellegs of the support 2I and located relatively close to the base portiony22 of the structure. Another pin 21 secured between the `legs of thesupport 2I at a place relatively remote from the base portion 22 has avprojection 29 which serves as an abutment or holder for a wire spring28. 'Ifhis Yspring is Wound around the pin 26 and mounted are subjectedto shock. The springs 4I through 44 have different diameters and,consequently, diierent stiffness. As a result, the natural frequenciesof the four oscillatory systems are diierent. These frequencies are sograduated that they cover the desiredl range within which the latchingdevice is intended to be operative.

The operation of each oscillatory system will be understood from thefollowing reference to Fig. 5 showing the weight 3`I in two differentpositions, both occurring 'during an oscillation. One of thesepositions-of weight 3| is shown in full lines while the other isrepresented in broken lines. During an oscillation, the' projection 5Iof the weight 3| will move towards the lever 23 and push it into thelatching position. Upon reversal of its oscillatory motion, the weight3| will move its projection 53 towards the lever 23, as shown in brokenlines,v again with the effect of moving the lever 23 into latchingposition. Consequently, as long as any of the four weights oscillates,the lever 23 will be held in the latching position.

Assuming that the contactor was in the contactopeningv position shown inFig. 3, the lever 23 when operative will prevent the latch 20 of thearmature from moving towards the closing position. This is apparent fromthe full-line showing of latch 20 in Fig. 5.

Assuming that the contacter was in the vcontact closing position beforethe occurrence of shock. the latch 2U of the armature will assume theposition shown in broken lines in Fig. v5. Consequently, the opening 25of the latching lever 23 will engage the latch 20 and prevent it fromleaving the contact closing position.

Since all four oscillatory systems operate the latching lever 23 in themanner just described, the latching device will be eective upon theoccurrence of any shock or vibration condition capable of causing anyvof the four systems to oscillate.

In the embodiment represented by Figs. 8 and 9, only two oscillatorysystems are provided while the latching device is otherwise designed inaccordance with the above described embodiment. The contactormay. alsohave the same construction as shown in the foregoing, although it willbe understood that devices according to my invention can be used toadvantage with other contactors or apparatus of any type in which amovable member is to be safeguarded against changes of position due toshock or vibration.

In the embodiment according to Figs. 8 and 9, the two oscillatoryweights are denoted by 35 and 31. Each of these weights is connectedwith a wire spring, such as spring 45 shown in Fig. 9. These springs arein engagement' with an extension of the latching lever similar toextension 36 in Figs e, 5, and '7. Weight 35 has two projections denotedby 53 and 54 for engaging the latching lever 23 in the manner describedin conjunction with the foregoing embodiment. The projection 54,however, is secured to the weight 35 by means of a screw 55 whichpermtis adjusting the distance between the projection and they Weight35. The weight 31 has similar projections, one of them being denoted by54' and provided with an adjusting screw 55'. The operation of thismodified systemA is similar to the one discussed in the foregoing.

It will be apparent from the foregoing description that since the rangeof shock or vibration frequencies to bev covered by the latching deviceis embraced by virtue of a multiplicity 0f oscillatory devices, thedamping of each of these devices need not be as great as is necessary inthe known vibration responsive devices `with only one oscillatorysystem. The reduction in damping thus afforded with respect to eachindividual oscillating system has the effect of increasing thesensitivity of response .to my device, and hence represents aconsiderable functional improve nient over the known latching apparatusof the vibratory type. As a result, my improved device responds morereadily to high and loW impact forces and does not require a specialadjustment of its individual oscillating system as regards thedeterminants of the oscillation characteristics.

Latching devices according Vto my invention form a unit separate fromthe contactor or other apparatus to be protected. Due to this fact, thelatching devices can be separably manufactured and assembled and areapplicable in connection with electric devices of different design andtype, it being only necessary to'provide the movable member or armatureof the device with a latch corresponding to part 2l) in theabove-described embodiment.

I am aware of the fact that latching devices according to my inventionmay be modified in various Ways without departing from the objectsand'essential features of my invention. Therefore, I intend theforegoing description to vbe understood as illustrative and not in alimiting sense.

I claim as my invention:

l.. A device for latching a movable member in response to the occurrenceof shock, comprising, combination, a support, two pivot shafts mountedon said support in parallel to each other, a latching lever mounted onone of said-shafts for angular motion and extending in the generaldirection towards and beyond said other shaft, a plurality of weightsmounted for individual angular motion on said other shaft and havingeach two projections at opposite sides of said latter shaft for engagingsaid lever in order to move it into latching position upon oscillationof any of said weights, a corresponding plurality of I crumed on saidApivot shaft vin parallel to one y said Weights and appertaining springsforming inertia controlled oscillatory systems of different naturalfrequencies.v

2'. A device for latching a movable member in response to the occurrenceof sh'ock, comprising a support, a latching lever fulcrumed on saidsupport for pivotal motion between a latching position and an unlatchingposition, a spring disposed between Vsaid support and said lever to biasthe latter towards inoperative position, a pivot shaft secured to saidsupport, a plurality of oscillatory systems cf vdifferent naturalfrequency having a *plurality of respective weights fulanother sothat-each is capable of independent oscillation for moving said latchmeans into latching position, `and a plurality of straight strand-shapedsprings attached to said Weights respectively and extendingsubstantially in parallel to one another. y

3. A device for latching a movable member in response to the occurrenceof shock, comprising movable latching means normally maintaining anunlatched position, and a plurality of mechanical oscillators ofdifferent oscillation characteristics arranged for individuallycontrolling said latching means to move into a, latching position uponoccurrence of shock, each ofsaid oscillators including a movable weightand a substantially straight piece of spring wire, saidwires havingsubstantially the same lengthrand different stiifness to provide fordifferent naturalfrequencies of said oscillators.

4. A `device for latching a movable member in response to the occurrenceof shock,k comprising,

in combination, a support, a lever pivoted on said Y support and forminga latch at its end remote from its pivot axis, said lever being biasedto vnormally assume an unlatched position, a plurality of Weightspivotally mounted on said support for individually engaging said leverbetween said end and said pivot axis, and a plurality of springs havingone end attached t0 said weights respectively and the other end inengagement with said lever at a point near said pivot axis, said weightsand respective springs forming inertia controlled oscillatory systems ofdifferent natural frequencies. Y y

5. A device for latching a movable member inv response to shock,comprising a support, a, latch lever pivoted to said support for motionbetween a latching position and an unlatching yposition and beingnormally biased toward said unlatching position, said lever having anend portion remote from its pivot axis arranged relative to said memberso as to'prevent movement of said member when said lever is in saidlatchingiposition, an inertia weight pivoted to said structure about anaxis extending in parallel to the pivot axis of said lever and arrangedadjacentto said lever substantially between ksaid latter pivot axis andsaid end portion so that said weight, when oscillating due to shock,causes said levery to move into said latching,v position, and anelongated spring having one end attached to said weight and Ahaving theother end in engagement with said lever near said pivot axis of saidlever.

strand-shaped springs having one end attached f Y RALPH Bf. IMMEL.

